Reactivity of nitrogen species with inorganic and organic compounds in water.

Many studies on the reactive nitrogen species (RNS, ●NO2, ●NO and ●NH2) with pollutants in water have been performed to understand the abatement of inorganic and organic compounds by these species, and the mechanisms of the formation of oxidative transformation products, especially nitrogenous oxidized byproducts. In this review, approaches to generate RNS in aqueous solution is first presented, followed by a summary of their reactivity with a wide range of compounds. The second-order rate constants (k, M-1 s-1) for the reactivity of ●NO2 and ●NO with a wide range of inorganic radical and nonradical species were correlated with thermodynamic one-electron oxidation potentials (E0). The positive correlation between log(k) versus E0 suggests one-electron transfer reactions. The Hammett-type correlations were developed for the reactions of ●NO2 and ●NH2 with organic compounds, using the unsubstituted benzene as a reference molecule (i.e., Σσo,p,m = 0) to calculate Σσo,p,m = σo + σp + σm for each organic molecule. Linear negative correlations of log(k) with Σσo,p,m were obtained for both ●NO2 and ●NH2, suggesting electrophilic substitution mechanism. The correlations presented herein may assist in eliminating organic micropollutants in water treatment and reuse processes.